array_intersect_ukey Computes the intersection of arrays using a callback function on the keys for comparison &reftitle.description; arrayarray_intersect_ukey arrayarray arrayarrays callablekey_compare_func array_intersect_ukey returns an array containing all the values of array which have matching keys that are present in all the arguments. &reftitle.parameters; array Initial array for comparison of the arrays. arrays Arrays to compare keys against. key_compare_func &return.callbacksort; &callback.cmp; &reftitle.returnvalues; Returns the values of array whose keys exist in all the arguments. &reftitle.examples; $key2) return 1; else return -1; } $array1 = array('blue' => 1, 'red' => 2, 'green' => 3, 'purple' => 4); $array2 = array('green' => 5, 'blue' => 6, 'yellow' => 7, 'cyan' => 8); var_dump(array_intersect_ukey($array1, $array2, 'key_compare_func')); ?> ]]> &example.outputs; int(1) ["green"]=> int(3) } ]]> In our example you see that only the keys 'blue' and 'green' are present in both arrays and thus returned. Also notice that the values for the keys 'blue' and 'green' differ between the two arrays. A match still occurs because only the keys are checked. The values returned are those of array. &reftitle.seealso; array_diff array_udiff array_diff_assoc array_diff_uassoc array_udiff_assoc array_udiff_uassoc array_diff_key array_diff_ukey array_intersect array_intersect_assoc array_intersect_uassoc array_intersect_key